Fossa ovalis penetration

ABSTRACT

A method is provided, including transvascularly inserting a guidewire into a right atrium of a subject. Apparatus is provided that includes (a) a catheter, and (b) a hollow needle disposed within a lumen of the catheter, the hollow needle including a proximal portion and a distal portion that is more flexible than the proximal portion. The apparatus is passed into the right atrium by passing the needle over the guidewire. Following the passing of the apparatus into the right atrium, the guidewire is partially withdrawn into the needle, while keeping a distal end of the guidewire within the needle and in a body of the subject. Thereafter, a hole is formed through an interatrial septum of the subject with the needle. Other embodiments are also described.

FIELD OF THE INVENTION

Applications of the present invention relate in general to the deliveryof therapeutic devices to the left atrium or ventricle of the heart.More specifically, applications of the present invention relate to (a)penetrating the fossa ovalis for the purpose of delivering therapeuticdevices, and/or (b) delivering an implant to the left atrial appendage.

BACKGROUND

Various pathologies call for the delivery of therapeutic devices, e.g.,valve repair or valve replacement devices, to the left atrium or leftventricle of the heart (i.e., the left side of the heart). In manyapplications, therapeutic devices are delivered to the left side of theheart by being passed through the vena cava, into the right atrium, andthrough the interatrial septum. Such delivery calls for apparatus andmethods for puncturing the interatrial septum. In many applications, thedesired site for puncture lies in the fossa ovalis, a region of theseptum containing tissue of lesser thickness than is typical of the restof the septum.

SUMMARY OF THE INVENTION

Applications of the present invention include apparatus for forming ahole through an interatrial septum, such as at a fossa ovalis. Theapparatus includes a catheter shaped to define a catheter lumen. Thewall of the catheter includes a braided portion, and is shaped to definefirst and second longitudinally-running channels therethrough. A distalportion of the catheter is shaped to define first and second lateralopenings, which are typically approximately equidistant from the distalend of the catheter. A wire passes through the first channel, out of thefirst channel via the first lateral opening, into the second channel viathe second lateral opening, and through the second channel. The wire isdeployed, i.e., pushed out of the catheter, such that the deployedportion of the wire is loop-shaped. The wire facilitates finding thefossa ovalis, and/or stabilizing the catheter as the fossa ovalis ispunctured.

Applications of the present invention also include a catheter that has awall having both a braided portion and an unbraided portion. Areinforcing tube at least partially surrounds the unbraided portion ofthe catheter wall. A control handle surrounds the catheter such that (a)all of the catheter wall that is distal to a distal end of the controlhandle comprises the braided portion, and (b) at least 10% of thecatheter wall that is proximal to the distal end of the control handlecomprises the unbraided portion.

Applications of the present invention also include various types ofhollow needles having flexible distal portions.

Applications of the present invention also include a method thatincludes transvascularly inserting a guidewire into a right atrium of asubject. Apparatus is provided that includes (a) a catheter, and (b) ahollow needle disposed within a lumen of the catheter, the hollow needleincluding a proximal portion and a distal portion that is more flexiblethan the proximal portion. The apparatus is passed into the right atriumby passing the needle over the guidewire. Following the passing of theapparatus into the right atrium, the guidewire is partially withdrawninto the needle, while keeping a distal end of the guidewire within theneedle and in a body of the subject. Thereafter, a hole is formedthrough an interatrial septum (e.g., at a fossa ovalis) with the needle.Typically, after the hole is formed through the interatrial septum, theguidewire is advanced into a left atrium of the subject, and,thereafter, the needle is proximally withdrawn from the right atrium.Typically, after the needle is proximally withdrawn from the rightatrium, a left-side therapeutic delivery system is introduced, over theguidewire, into the left atrium.

In general, apparatus and methods described herein can also be used topenetrate other body orifices. (In this context, penetration of the bodyorifice might not include puncturing with a puncturing element, as istypically the case for the fossa ovalis.) For example, apparatus andmethods described herein can be used to pass a catheter and/or atherapeutic device through the coronary sinus ostium and into thecoronary sinus. Furthermore, apparatus and methods described herein canalso be used to locate an opening, natural or manmade, in a portion ofanatomy. For example, apparatus and methods described herein can be usedto locate the coronary sinus ostium, a natural opening in the fossaovalis, or a puncture in the fossa ovalis. In some applications,apparatus described herein may be further configured to deliver a plug(e.g., an Amplatzer™), or other such stopping device, to the opening.

There is therefore provided, in accordance with an application of thepresent invention, a method including:

transvascularly inserting a guidewire into a right atrium of a subject;

providing apparatus that includes (a) a catheter and (b) a hollow needledisposed within a lumen of the catheter, the hollow needle including aproximal portion and a distal portion that is more flexible than theproximal portion;

passing the apparatus into the right atrium by passing the needle overthe guidewire;

following the passing of the apparatus into the right atrium, partiallywithdrawing the guidewire into the needle, while keeping a distal end ofthe guidewire within the needle and in a body of the subject; and

thereafter, forming a hole through an interatrial septum of the subjectwith the needle.

For some applications, the method further includes, after forming thehole through the interatrial septum, advancing the guidewire into a leftatrium of the subject.

For some applications, the method further includes, after advancing theguidewire into the left atrium, proximally withdrawing the needle fromthe right atrium.

For some applications, the method further includes, after proximallywithdrawing the needle from the right atrium, introducing, over theguidewire, a left-side therapeutic delivery system into the left atrium.

For some applications, proximally withdrawing the needle from the rightatrium includes leaving the catheter in the right atrium, andintroducing the left-side therapeutic delivery system includesintroducing the left-side therapeutic delivery system through thecatheter.

For some applications:

the method further includes, before introducing the left-sidetherapeutic delivery system into the left atrium, advancing the catheterdistally through the hole into the left atrium, and

introducing the left-side therapeutic delivery system into the leftatrium includes advancing the left-side therapeutic delivery systemthrough the catheter into the left atrium.

For some applications, forming the hole through the interatrial septumincludes forming the hole through a fossa ovalis of the subject.

For some applications, forming the hole through the interatrial septumincludes puncturing the interatrial septum with a sharp distal tip ofthe needle.

For some applications, forming the hole through the interatrial septumincludes applying energy to the interatrial septum with the needle.

For some applications, the method further includes, before forming thehole through the interatrial septum:

deploying at least one fossa-ovalis-finding loop from a wall of thecatheter; and

moving the fossa-ovalis-finding loop along the interatrial septum, untilthe fossa-ovalis-finding loop contacts a fossa ovalis of the subject.

For some applications, partially withdrawing the guidewire includespartially withdrawing the guidewire a distance of less than 50 cm.

For some applications, the apparatus further includes afluid-impermeable cover surrounding the distal portion of the needle.

For some applications, the method further includes measuring, using apressure sensor disposed in fluid communication with a proximal end ofthe needle, a pressure at a distal tip of the needle.

For some applications:

the apparatus further includes a dilator element, which is shaped todefine a dilator lumen and to be slidably disposed within the lumen ofthe catheter,

the needle is slidably disposed within the dilator lumen, and

the method further includes dilating the hole using the dilator element.

For some applications, the method further includes, after dilating thehole, advancing the catheter distally through the dilated hole into aleft atrium of the subject.

For some applications, the hollow needle further includes a distal-mostend portion that is less flexible than the flexible distal portion.

For some applications, the catheter is a puncture-tool catheter, andwherein passing the apparatus into the right atrium includes:

inserting a delivery catheter of a left-side therapeutic delivery systeminto the right atrium; and

advancing the puncture-tool catheter through the delivery catheter intothe right atrium.

For some applications, the distal portion of the hollow needle ishelical.

There is still further provided, in accordance with an application ofthe present invention, a method including:

inserting a catheter into a right atrium of a heart of

the subject;

advancing a distal portion of the catheter toward a fossa ovalis of theheart;

deploying a flexible longitudinal member from the catheter, such that adeployed portion of the flexible longitudinal member is loop-shaped;

contacting the fossa ovalis with the deployed portion of the flexiblelongitudinal member;

deploying a needle from the catheter;

bringing a distal end of the needle in contact with a site on a surfaceof an interatrial septum of the heart outside the fossa ovalis;

forming a hole through the interatrial septum at the site with theneedle; and

withdrawing the deployed portion of the flexible longitudinal membertoward the catheter.

For some applications, forming the hole through the interatrial septumincludes puncturing the interatrial septum with a sharp distal tip ofthe needle.

For some applications, forming the hole through the interatrial septumincludes applying energy to the interatrial septum with the needle.

For some applications, contacting the fossa ovalis with the deployedportion of the flexible longitudinal member includes contacting an innerperimeter of the fossa ovalis.

For some applications, the method further includes, before contactingthe fossa ovalis with the deployed portion of the flexible longitudinalmember, moving the deployed portion of the flexible longitudinal memberalong the surface of the interatrial septum, until the flexiblelongitudinal member contacts the fossa ovalis.

For some applications, moving the deployed portion of the flexiblelongitudinal member along the surface of the interatrial septum includesmoving the deployed portion of the flexible longitudinal member towardthe fossa ovalis from below the fossa ovalis.

For some applications, deploying the flexible longitudinal memberincludes deploying the flexible longitudinal member such that adeployment angle of the flexible longitudinal member is between 10 and80 degrees,

the deployment angle being an angle between (a) a vector that is (i)tangent to the flexible longitudinal member at an exit point of theflexible longitudinal member from the catheter, and (ii) directed awayfrom the catheter, and (b) a distally-directed vector that is parallelto a longitudinal axis of the catheter at the exit point.

For some applications, deploying the flexible longitudinal memberincludes deploying the flexible longitudinal member such that thedeployment angle is between 30 and 60 degrees.

For some applications, deploying the flexible longitudinal member fromthe catheter includes passing the flexible longitudinal member throughtwo lateral openings at a distal portion of the catheter.

For some applications, the flexible longitudinal member is radiopaque,and the method further includes using fluoroscopic imaging to view theflexible longitudinal member during and after deployment thereof.

For some applications, the method further includes, before forming thehole through the interatrial septum, flexing a distal portion of theneedle by steering the catheter.

For some applications, the catheter is a puncture-tool catheter, andinserting the catheter into the right atrium includes:

inserting a delivery catheter of a left-side therapeutic delivery systeminto the right atrium; and

advancing the puncture-tool catheter through the delivery catheter intothe right atrium.

There is additionally provided, in accordance with an application of thepresent invention, a method including:

inserting a catheter into a right atrium of a heart of a subject;

advancing a distal portion of the catheter toward a roof of the rightatrium;

deploying a flexible longitudinal member from the catheter, such that adeployed portion of the flexible longitudinal member is loop-shaped;

contacting, with the deployed portion of the flexible longitudinalmember, a stabilization site located (a) on the roof of the rightatrium, (b) between the roof and an interatrial septum of the heart, or(c) on the interatrial septum superior to a fossa ovalis of the heart;

deploying a needle from the catheter;

bringing a distal end of the needle in contact with a hole site on asurface of the interatrial septum;

forming a hole through the interatrial septum at the hole site with theneedle; and

withdrawing the deployed portion of the flexible longitudinal membertoward the catheter.

For some applications, forming the hole through the interatrial septumincludes puncturing the interatrial septum with a sharp distal tip ofthe needle.

For some applications, forming the hole through the interatrial septumincludes applying energy to the interatrial septum with the needle.

For some applications, deploying the flexible longitudinal member fromthe catheter includes passing the flexible longitudinal member throughtwo lateral openings at a distal portion of the catheter.

For some applications, the flexible longitudinal member is radiopaque,and the method further includes using fluoroscopic imaging to view theflexible longitudinal member during and after deployment thereof.

For some applications, the method further includes, before forming thehole through the interatrial septum, flexing a distal portion of theneedle by steering the catheter.

For some applications, the catheter is a puncture-tool catheter, andinserting the catheter into the right atrium includes:

inserting a delivery catheter of a left-side therapeutic delivery systeminto the right atrium; and

advancing the puncture-tool catheter through the delivery catheter intothe right atrium.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a catheter shaped to define a catheter lumen,        -   a wall of which catheter (a) comprising a braided portion            having an outer surface, an inner surface, and a braided            interior between the outer and inner surfaces, and (b) being            shaped to define a first longitudinally-running channel            therethrough and a second longitudinally-running channel            therethrough, and        -   a distal portion of which catheter being shaped to define a            first lateral opening and a second lateral opening, an angle            between (a) a first line running between the first and            second lateral openings, and (b) a second line that is            parallel to a central longitudinal axis of the catheter when            the catheter is straight, being between 30 and 150 degrees;            and

a flexible longitudinal member that passes (a) from a proximal portionof the catheter to the distal portion of the catheter via the firstchannel, (b) out of the first channel via the first lateral opening, (b)into the second channel via the second lateral opening, and (c) from thedistal portion of the catheter to the proximal portion of the cathetervia the second channel.

In some applications, the angle between the first and second lines isbetween 60 and 120 degrees.

In some applications, the angle between the first and second lines isbetween 80 and 100 degrees.

In some applications, the first and second openings are separated fromone another by an angle of 170-190 degrees measured along acircumference of the catheter.

In some applications, the apparatus further includes a needle shaped tobe slidably disposed within the catheter lumen.

In some applications, the needle is electrically conductive, and theapparatus further comprises:

one or more conductors; and

a controller, which is coupled to the needle by the conductors, andwhich is configured to drive the needle to apply energy capable ofcreating a hole through tissue.

In some applications, the apparatus further includes:

a dilator element shaped to be slidably disposed within the catheterlumen, the dilator element being shaped so as to define a dilator lumen;and

a dilator tip disposed at a distal end of the dilator element, thedilator tip being configured to dilate an opening created by the needle.

In some applications, the needle is shaped to be slidably disposedwithin the dilator lumen.

In some applications, the flexible longitudinal member is mechanicallyresilient.

In some applications, a diameter of the flexible longitudinal member isbetween 0.1 and 0.5 mm.

In some applications, the flexible longitudinal member includes a wire.

In some applications, the flexible longitudinal member includes amaterial selected from the group consisting of: nitinol, stainlesssteel, and chromium cobalt.

In some applications, the flexible longitudinal member is configured tobe deployed such that, in an absence of any force applied to thedeployed portion of the flexible longitudinal member by an element thatis not part of the apparatus, a deployment angle of the flexiblelongitudinal member is between 10 and 80 degrees,

the deployment angle being an angle between (a) a vector that is (i)tangent to the flexible longitudinal member at an exit point of theflexible longitudinal member from the catheter, and (ii) directed awayfrom the catheter, and (b) a distally-directed vector that is parallelto a longitudinal axis of the catheter at the exit point.

In some applications, the flexible longitudinal member is configured tobe deployed such that, in the absence of any force applied to thedeployed portion of the flexible longitudinal member by an element thatis not part of the apparatus, the deployment angle is between 30 and 60degrees.

In some applications, the flexible longitudinal member is radiopaque.

In some applications, the apparatus further includes a plurality ofradiopaque markers coupled to the flexible longitudinal member.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a catheter having a catheter wall that comprises:        -   a braided portion having an outer surface, an inner surface,            and a braided interior between the outer and inner surfaces;            and        -   an unbraided portion having an unbraided interior;

a control element shaped to surround a proximal portion of the cathetersuch that (a) all of the catheter wall that is distal to a distal end ofthe control element comprises the braided portion, and (b) at least 10%of the catheter wall that is proximal to the distal end of the controlelement comprises the unbraided portion; and

a reinforcing tube at least partially surrounding the unbraided portion.

In some applications,

a wall of the reinforcing tube is shaped to define one or more lateralopenings therethrough,

the catheter wall is shaped to define one or more longitudinally-runningchannels therethrough, and

the apparatus further comprises one or more flexible longitudinalmembers passing through the lateral openings and through thelongitudinally-running channels.

In some applications, the flexible longitudinal members are coupled tothe control element.

In some applications, a length of the braided portion is between 600 and1000 mm.

In some applications, a length of the unbraided portion is between 250and 400 mm.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a helical distal portion having an outer diameter between            0.5 and 1.5 mm and a length between 50 and 200 mm; and

a fluid-impermeable cover surrounding the helical distal portion of theneedle.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a laser-cut distal portion having an outer diameter between            0.5 and 1.5 mm and a length between 50 and 200 mm; and

a fluid-impermeable cover surrounding the laser-cut distal portion ofthe needle.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion (a) having an outer diameter between 0.5            and 1.5 mm and a length between 50 and 200 mm, and (b)            comprising a wall that is shaped to define a plurality of            openings that pass completely therethrough; and

a fluid-impermeable cover surrounding the laser-cut distal portion ofthe needle.

In some applications, the wall of the distal portion of the hollowneedle is shaped to define a plurality of slits therethrough.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion comprising an elastomeric tube having an            outer surface, an inner surface, and an interior portion            between the outer and inner surfaces that is selected from            the group consisting of: a braided metal interior, and a            coiled metal interior,        -   the distal portion having an outer diameter between 0.5 and            1.5 mm and a length between 50 and 200 mm.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion at least partially made of nitinol, the            distal portion having an outer diameter between 0.5 and 1.5            mm and a length between 50 and 200 mm.

There is further provided, in accordance with some applications of thepresent invention, a method for puncturing a fossa ovalis of a heart,the method including:

inserting a catheter into a right atrium of the heart;

advancing a distal portion of the catheter toward the fossa ovalis;

deploying a flexible longitudinal member and a needle from the catheter,such that (a) a deployed portion of the flexible longitudinal member isloop-shaped, and (b) the needle is on a first side of the deployedportion of the flexible longitudinal member;

contacting the fossa ovalis with the deployed portion of the flexiblelongitudinal member;

passing a distal end of the needle through the deployed portion of theflexible longitudinal member to a second side of the deployed portion ofthe flexible longitudinal member that is opposite the first side, andpuncturing the fossa ovalis with the needle; and

while the distal end of the needle is on the second side of the deployedportion of the flexible longitudinal member, withdrawing the deployedportion of the flexible longitudinal member toward the catheter.

In some applications, contacting the fossa ovalis with the deployedportion of the flexible longitudinal member includes contacting an innerperimeter of the fossa ovalis.

In some applications, the method further includes, before contacting thefossa ovalis with the deployed portion of the flexible longitudinalmember, moving the deployed portion of the flexible longitudinal memberalong a surface of an interatrial septum of the heart, until theflexible longitudinal member contacts the fossa ovalis.

In some applications, moving the deployed portion of the flexiblelongitudinal member along the surface of the interatrial septum includesmoving the deployed portion of the flexible longitudinal member towardthe fossa ovalis from below the fossa ovalis.

In some applications, deploying the flexible longitudinal memberincludes deploying the flexible longitudinal member such that adeployment angle of the flexible longitudinal member is between 10 and80 degrees,

the deployment angle being an angle between (a) a vector that is (i)tangent to the flexible longitudinal member at an exit point of theflexible longitudinal member from the catheter, and (ii) directed awayfrom the catheter, and (b) a distally-directed vector that is parallelto a longitudinal axis of the catheter at the exit point.

In some applications, deploying the flexible longitudinal memberincludes deploying the flexible longitudinal member such that thedeployment angle is between 30 and 60 degrees.

In some applications, deploying the flexible longitudinal member fromthe catheter includes passing the flexible longitudinal member throughtwo lateral openings at a distal portion of the catheter.

In some applications, the flexible longitudinal member is radiopaque,and the method further includes using fluoroscopic imaging to view theflexible longitudinal member during and after deployment thereof.

In some applications, the method further includes, before puncturing thefossa ovalis, flexing a distal portion of the needle by steering thecatheter.

In some applications, the catheter is a puncture-tool catheter, andinserting the puncture-tool catheter into the right atrium includes:

inserting a delivery catheter of a left-side therapeutic delivery systeminto the right atrium; and

advancing the puncture-tool catheter through the delivery catheter intothe right atrium.

There is further provided, in accordance with some applications of thepresent invention, a method for puncturing a fossa ovalis of a heart,the method including:

inserting a catheter into a right atrium of the heart;

advancing the catheter toward an interatrial septum of the heart;

subsequently, inserting a needle into a lumen of the catheter;

flexing a distal portion of the needle by steering the catheter; and

following the flexing of the distal portion of the needle, using theneedle to puncture the fossa ovalis.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a helical distal portion; and

a fluid-impermeable cover surrounding the helical distal portion of theneedle.

In some applications, the fluid-impermeable cover fits snugly around thehelical distal portion of the needle.

In some applications, the proximal portion has an outer diameter between0.7 and 3 mm.

In some applications, the proximal portion has a length between 650 and1200 mm.

In some applications, the proximal portion has a wall thickness between0.1 and 0.3 mm.

In some applications, the distal portion has an outer diameter between0.5 and 1.5 mm.

In some applications, the distal portion has a length between 30 and 200mm.

In some applications, the distal portion has a length between 30 and 100mm.

In some applications, the helical distal portion includes ahelically-cut tube.

In some applications, the helical distal portion includes one or morecoiled wires.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a distal portion that is more flexible than the proximal            portion; and

a fluid-impermeable cover surrounding the distal portion of the needle.

In some applications, the distal portion includes a wall that is cut atone or more locations between longitudinal ends of the wall.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a distal portion including a wall that is shaped to define a            plurality of openings that pass completely therethrough; and

a fluid-impermeable cover surrounding the distal portion of the needle.

In some applications, the wall of the distal portion of the hollowneedle is shaped to define 25-250 openings.

In some applications, the wall of the distal portion of the hollowneedle is shaped to define a plurality of slits therethrough.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a distal portion including an elastomeric tube having an            outer surface, an inner surface, and an interior portion            between the outer and inner surfaces that is selected from            the group consisting of: a braided metal interior, and a            coiled metal interior.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion at least partially made of nitinol, the            distal portion having an outer diameter between 0.5 and 1.5            mm and a length between 30 and 200 mm.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

a tube shaped to define a tube lumen, a reduced-diameter portion of thetube lumen that is between 5 and 30 mm of a distal end of the tubehaving a diameter that is reduced, relative to a portion of the tubelumen that is proximal to the reduced-diameter portion; and

-   -   a hollow needle, including:        -   a proximal portion;        -   a distal portion that is more flexible than the proximal            portion; and        -   a distal-most end portion that is distal to the distal            portion and is less flexible than the distal portion, the            distal-most end portion including an increased-diameter            portion having a diameter that is greater than another part            of the distal-most end portion,

the diameter of the reduced-diameter portion of the tube lumen being (a)less than an outer diameter of the increased-diameter portion, and (b)greater than an outer diameter of the other part of the distal-most endportion.

In some applications, the distal-most end portion has a length between10 and 30 mm.

In some applications, the increased-diameter portion is disposed at aproximal end of the distal-most end portion.

In some applications, the outer diameter of the increased-diameterportion is greater than an outer diameter of the distal portion.

The present invention will be more fully understood from the followingdetailed description of applications thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-G are schematic illustrations of apparatus for puncturing afossa ovalis of a subject, in accordance with some applications of thepresent invention;

FIGS. 2A-B are schematic illustrations of a cross-section of a wall of acatheter, in accordance with some applications of the present invention;

FIG. 3 is a schematic illustration of a catheter, in accordance withsome applications of the present invention;

FIGS. 4-7 are schematic illustrations of hollow needles having flexibledistal portions, in accordance with some applications of the presentinvention;

FIG. 8 is a schematic illustration of apparatus used, for example, forfossa ovalis penetration, in accordance with some applications of thepresent invention;

FIG. 9 is a flow chart showing the steps in a prior-art method forpuncturing a fossa ovalis and delivering treatment to a left side of aheart;

FIG. 10 is a flow chart showing the steps in a method for puncturing afossa ovalis with a hollow needle, in accordance with some applicationsof the present invention;

FIGS. 11A-B are schematic illustrations of an alternative method fordelivering a left-side therapeutic delivery system to the left side ofthe heart, in accordance with an application of the present invention;

FIG. 12 is a schematic illustration of an alternative method of usingthe apparatus described herein, in accordance with an application of thepresent invention;

FIG. 13 is a schematic illustration of an alternative method of usingthe apparatus described herein, in accordance with an application of thepresent invention;

FIG. 14 is a schematic illustration of the use of the apparatusdescribed herein in combination with a left-side therapeutic deliverysystem, in accordance with an application of the present invention;

FIG. 15 is a schematic illustration of a configuration of the apparatusdescribed herein, in accordance with an application of the presentinvention;

FIG. 16 is a schematic illustration of a method for puncturing the fossaovalis, in accordance with some applications of the present invention;and

FIGS. 17-18 are schematic illustrations of a catheter, in accordancewith some applications of the present invention.

DETAILED DESCRIPTION OF APPLICATIONS

Reference is now made to FIGS. 1A-G, which are schematic illustrationsof apparatus 34 for puncturing a fossa ovalis 18 of a subject, and amethod of using apparatus 34, in accordance with some applications ofthe present invention. Apparatus 34 comprises a catheter 38, which mayalso be referred to by those in the field as an introducer tube.Catheter 38 is shaped to define a catheter lumen 52.

Reference is also made to FIGS. 2A-B, which are schematic illustrationsof a cross-section of a wall 39 of catheter 38, in accordance with someapplications of the present invention. Wall 39 comprises a braidedportion 41 (shown in FIG. 2A), which has an outer surface 45, an innersurface 47, and a braided interior 53 between outer surface and innersurface 47. Wall 39 also comprises an unbraided portion 43 (shown incross-section in FIG. 2B), which is typically disposed proximally tobraided portion 41. (Braided portion 41 and unbraided portion 43 aredescribed in more detail hereinbelow with reference to FIGS. 17-18.)Wall 39 is shaped to define a first longitudinally-running channel 27 aand a second longitudinally-running channel 27 b therethrough. (Channels27 a and 27 b run through both the braided and unbraided portions.) Adistal portion of catheter 38 is shaped to define a first lateralopening 26 a and a second lateral opening 26 b (shown in FIG. 1A). Aflexible longitudinal member 14 (e.g., a wire) passes (a) from aproximal portion of the catheter to the distal portion of the cathetervia first channel 27 a, (b) out of first channel 27 a via first lateralopening 26 a, (c) into second channel 27 b via second lateral opening 26b, and (d) from the distal portion of the catheter to the proximalportion of the catheter via second channel 27 b.

Typically, flexible longitudinal member 14 is mechanically resilient,i.e., it does not readily buckle upon being subjected to a compressiveforce, as would, for example, a string. The flexible longitudinal membertypically comprises nitinol, stainless steel, and/or chromium cobalt,and typically has a diameter D that is at least 0.1 mm and/or less than0.5 mm.

Reference is now made to FIG. 3, which is a schematic illustration ofcatheter 38, in accordance with some applications of the presentinvention. Typically, first and second openings 26 a and 26 b aredisposed at substantially the same distance from the distal end of thecatheter. An advantage of this disposition is that the loop may bedeployed in a forward-facing direction, rather than laterally. Forexample, an angle alpha between (a) a first line 76 running between thefirst and second lateral openings, and (b) a second line 78 that isparallel to a central longitudinal axis of the catheter when thecatheter is straight, may be at least 30 and/or less than 150 degrees,e.g., between 60 and 120 degrees, e.g., between 80 and 100 degrees. (Anangle alpha of 90 degrees implies that the first and second openings aredisposed at the same distance from the distal end of the catheter.)Alternatively or additionally, the distance of one opening from thedistal end of the catheter differs by less than 1 cm from the distanceof the other opening.

Further typically, the first and second openings are separated from oneanother by an angle beta of at least 170 degrees and/or less than 190degrees (e.g., 180 degrees) measured along a circumference of thecatheter. Thus, when the flexible longitudinal member is in itswithdrawn position, it “occupies” only 170-190 degrees around theoutside surface of the catheter, both prior to deployment and followingwithdrawal. In contrast, if beta were farther away from 180 degrees, thewithdrawn flexible longitudinal member might occupy a relatively largeangle, either prior to deployment or following withdrawal. For example,if beta were 90 degrees, the flexible longitudinal member wouldtypically occupy 270 degrees either prior to deployment or followingwithdrawal, if, as described hereinbelow with reference to FIG. 1E, thedeployment and withdrawal of the flexible longitudinal member are donefrom/toward opposite sides of the catheter. It is typically preferredthat such a large portion of the flexible longitudinal member not bedisposed outside of the catheter when the flexible longitudinal memberis in its withdrawn position, since the risk of collateral damage totissue typically increases as more of the flexible longitudinal memberis exposed. The angle beta of 170-190 degrees is thus advantageous,particularly when the deployment and withdrawal are done from/toopposite sides of the catheter. (It is noted that for some procedures orfor some patients, an angle beta outside of 170-190 degrees isappropriate.)

Reference is now made to FIGS. 4-7, which are schematic illustrations ofa hollow needle 32 having a flexible distal portion 88, in accordancewith some applications of the present invention. The applications shownin FIGS. 4-7 are similar to each other in function; they differ fromeach other mainly in the structure of flexible distal portion 88. Anadvantage of needle 32 is that flexible distal portion 88 of the needleis more flexible than other portions of the needle (e.g., than aproximal portion 90 of the needle), such that flexible distal portion88, while inside the catheter lumen, may be flexed by steering thecatheter. Another advantage of flexible distal portion 88 of needle 32is that if the needle were instead stiff, rather than flexible, theneedle might cut the guidewire as a sharp distal tip of the needle isforced against the outer surface of the guidewire during advancement ofthe needle over the guidewire.

Needle 32 comprises proximal portion 90, which generally runs throughmost of the length of the catheter, and which is used to transferpushing force to the distal portion of the needle (and is thereforetypically stiffer than flexible distal portion 88). Proximal portion 90typically has an outer diameter D1 that is at least 0.7 mm and/or lessthan 3 mm, and/or a length L3 that is at least 650 mm and/or less than1200 mm, and/or a wall thickness t1 that is at least 0.1 mm and/or lessthan 0.3 mm. Flexible distal portion 88 typically has an outer diameterD2 that is at least 0.5 mm and/or less than 1.5 mm, and/or a length L4that is at least 30 mm and/or less than 200 mm, e.g., between 30 and 100mm. Needle 32 also comprises a distal-most end portion 94, which is lessflexible than flexible distal portion 88, and is typically relativelyrigid. (The relative rigidity of distal-most end portion 94 facilitatesthe puncturing function of the needle.) In some applications, thedistal-most end portion comprises an increased-diameter portion 104having a diameter that is greater than the other part of the distal-mostend portion. Increased-diameter portion 104 is typically disposed at theproximal end of the distal-most end portion. The function of theincreased-diameter portion is described below with reference to FIG. 8.

In FIG. 4, flexible distal portion 88 of the needle comprises anelastomeric tube 96 having an outer surface 97, an inner surface 99, anda braided and/or coiled metal interior 98 between the inner and outersurfaces. (Thus flexible distal portion 88 may be structurally similarto the braided portion of the catheter, shown in FIG. 2A.) Elastomerictube 96 provides flexibility to flexible distal portion 88. Braidedand/or coiled metal interior 98 reinforces the elastomeric tube suchthat it is less susceptible to buckling, and also facilitates thetransfer of electric current between the distal and proximal ends of theneedle. The transfer of electric current may be used to verify that theneedle has punctured the fossa ovalis, and/or apply an ablating current,e.g., a radiofrequency (RF) current, or other energy (e.g., heat,ultrasound, or light (e.g., laser) energy) to puncture the fossa ovalis.

The applications of FIGS. 5-6 are similar to that of FIG. 4 in that (a)the dimensions of flexible distal portion 88 and proximal portion 90 aregenerally as described above, and (b) flexible distal portion 88 is moreflexible than other portions of the needle. (The applications of FIGS.5-6 also provide for the transfer of electric current via flexibledistal portion 88.) The applications of FIGS. 5-6 differ from that ofFIG. 4 in that the flexibility of the distal portion is facilitated bythe helical configuration of the distal portion, rather than byelastomeric tube 96. The helical configuration of the distal portion maybe achieved, for example, by cutting (e.g., laser-cutting) a tube (e.g.,a metallic tube), as in FIG. 5, or by coiling one or more wires (e.g.,metallic wires), as in FIG. 6.

The application of FIG. 7 is similar to those of FIGS. 5-6 in that (a)the dimensions of flexible distal portion 88 and proximal portion 90 aregenerally as described above, and (b) flexible distal portion 88 is moreflexible than other portions of the needle. Furthermore, the applicationof FIG. 7 is similar to that of FIG. 5 in that the respectiveconfigurations of the distal portions may be achieved via cutting (e.g.,laser-cutting) a tube wall at one or more locations between longitudinalends of the wall. (The application of FIG. 7 also provides for thetransfer of electric current via flexible distal portion 88.) Theapplication of FIG. 7 differs from those of FIGS. 5-6 in that theflexibility of flexible distal portion 88 is facilitated by the wall ofthe flexible distal portion being shaped to define a plurality ofopenings 102 (e.g., slits) that pass completely therethrough. Typically,the number of openings 102 is at least 25 and/or less than 250.

For the applications of FIGS. 5-7, in order to keep the lumen of theneedle fluidly isolated from the needle's environment, afluid-impermeable cover 100 (e.g., a polymer film) surrounds (e.g., fitssnugly around) the distal portion of the needle. (Also typically, thedistal portion is internally lined by a lining such as a polymer film.)By keeping the lumen of the needle fluidly isolated, fluid-impermeablecover 100 facilitates measurement, using a pressure sensor disposed influid communication with the proximal end of the needle, of the pressureat the distal tip of the needle. (Elastomeric tube 96, shown in FIG. 4,is also fluid-impermeable, and also facilitates pressure measurements.)

In general, flexible distal portion 88 may include various combinationsor subcombinations of elements from FIGS. 4-7. Furthermore, in someapplications, flexible distal portion 88 comprises a portion that is atleast partially made of nitinol; for example, braided and/or coiledmetal interior 98 (FIG. 4) may be at least partially made of nitinol.The nitinol provides flexibility to flexible distal portion 88, whilealso facilitating the transfer of electric current. Similarly,distal-most end portion 94 and/or proximal portion 90 may be at leastpartially made of nitinol. Typically, portions of the flexible needlesof FIGS. 4-7 include stainless steel and/or another metal such astitanium, alternatively or additionally to nitinol.

Reference is now made to FIG. 8, which is a schematic illustration ofapparatus 106 used, for example, for fossa ovalis penetration, inaccordance with some applications of the present invention. Apparatus106 includes a tube, such as a dilator element 49, shaped to define atube lumen 108. A reduced-diameter portion 110 of the tube lumen islocated at a distance d from the distal end of the tube, d being atleast 5 mm and/or less than 30 mm. Reduced-diameter portion 110, whichmay include a protrusion and/or a narrowing of the tube lumen, has adiameter D3 that is reduced, relative to a portion of the tube lumenthat is proximal to the reduced-diameter portion. For example, in FIG.8, the portion of the tube lumen that is proximal to thereduced-diameter portion has a diameter D4 that is greater than D3.

Apparatus 106 also includes hollow needle 32, described hereinabove withreference to FIGS. 4-7. Diameter D3 of the reduced-diameter portion ofthe tube lumen is less than the outer diameter D5 of increased-diameterportion 104 of the distal-most end portion of the needle, but is greaterthan the outer diameter D6 of the other part of the distal-most endportion. Hence, only the part of the distal-most end portion that isdistal to the increased-diameter portion advances past thereduced-diameter portion of the tube lumen. (Typically, diameter D5 isalso greater than outer diameter D2 of flexible distal portion 88.)

In some applications, distal-most end portion 94 has a length L that isat least 10 mm and/or less than 30 mm. In some applications, theincreased-diameter portion is formed by attaching a ring to part of thedistal-most end portion of the needle. The ring is attached at adistance from the distal tip of the needle that corresponds to thedesired amount of protrusion of the needle. (Typically, the ring ispermanently attached.) In other applications, the distal-most endportion of the needle is shaped during manufacture to define theincreased-diameter portion.

Reference is made to FIGS. 4-8. It is noted that the use of hollowneedle 32 may be particularly advantageous when flexible longitudinalmember 14 (or other fossa-ovalis-locating-facilitating apparatus, suchas those described in US 2014/0309675 to Maisano, which is incorporatedherein by reference) is deployed from the catheter. Flexiblelongitudinal member 14 provides a “buffer” between the catheter andseptum (see FIG. 1C), allowing the catheter to be steered withoutsignificant risk of accidentally puncturing the septum. In other words,without flexible longitudinal member 14, it might not be practical tosteer the catheter, even if the needle were to have a flexible distalportion. Thus there is a particular synergy that is obtained whenflexible longitudinal member 14 is used together with hollow needle 32.

Reference is now made to FIG. 9, which is a flow chart showing aprior-art method for puncturing a fossa ovalis and delivering treatmentto a left side of a heart. Part of the prior-art method depicted in FIG.9 is described in (i) an Instructions for Use (IFU) document for the BRK(TM) Transseptal Needle, dated Mar. 25, 2010, released by St. JudeMedical, and (ii) an IFU document for the Swartz (TM) BraidedTransseptal Guiding Introducer, dated Feb. 4, 2010, also released by St.Jude Medical.

In the prior-art method, the needle is pre-shaped, and thus cannot bepassed over a guidewire, lest the needle tear through or otherwisedistort the guidewire. (Such tearing and/or distortion would inhibitperformance of the procedure, and, furthermore, would typically resultin the needle damaging the dilator and/or catheter.) Therefore, afterpassing the catheter over the guidewire, the guidewire is completelywithdrawn from the lumen of the catheter before the needle is inserted.Following the puncturing of the fossa ovalis and the passing of thecatheter to the left side of the heart, the needle is withdrawn from thelumen of the catheter. The guidewire is then reinserted into thecatheter and deployed into the left side of the heart, in order tofacilitate the subsequent delivery of treatment to the left side of theheart.

In contrast with the prior art, an advantage of hollow needle 32 is thatthe needle typically does not require pre-shaping before being loadedinto catheter 38, since, as noted above, the flexibility of flexibledistal portion 88 of hollow needle 32 generally allows the needle to beflexed into its desired orientation while it is inside the catheter.Hence, the guidewire need not necessarily be withdrawn before insertionof the needle, since hollow needle 32 may be passed over the guidewire.Furthermore, following the passing of the catheter to the left side ofthe heart, the needle need not necessarily be withdrawn from thecatheter to facilitate the deployment of the guidewire into the leftside of the heart, since the guidewire may be deployed through the lumenof the needle. Thus the flexibility of the distal portion of hollowneedle 32 may help shorten the time required to perform the procedureand simply the procedure.

Reference is now made to FIG. 10, which is a flow chart showing thesteps of a method 151 for puncturing a fossa ovalis with hollow needle32, in accordance with some applications of the present invention.Reference is also made again to FIGS. 1A-G. This method utilizes some ofthe above-noted advantages of hollow needle 32. In method 151, apparatusthat includes at least catheter 38 and hollow needle 32 is provided.Typically, the provided apparatus further includes other elements, suchas dilator element 49 and flexible longitudinal member 14.

At a guidewire-insertion step 152, a guidewire 60 is transvascularlyinserted into the right atrium of the subject, typically by insertingthe guidewire into a vein in the pelvic area of the subject (e.g., thefemoral vein), and advancing the guidewire toward the heart through theinferior vena cava.

At an apparatus-passing step 154, apparatus 34 is passed into the rightatrium by passing needle 32 (together with catheter 38, inside which theneedle is disposed) over guidewire 60, as shown in FIG. 1A. (As notedabove, there is typically no need to withdraw the guidewire beforepassing the needle into the right atrium.) Typically, dilator element49, which is shaped to define a dilator lumen, is shaped to be slidablydisposed within the catheter lumen, and the needle is shaped to beslidably disposed within the dilator lumen. The needle is inserted intothe dilator lumen, and is advanced up to a tip 16 of the dilatorelement. (Although dilator element 49 may also be embodied as acatheter, the present description refers exclusively to catheter 38—the“introducer tube”—as a catheter.) (Typically, catheter 38 is containedwithin the lumen of a sheath during parts of the insertion and/orwithdrawal of the catheter, such as to reduce the risk of damage tosurrounding tissue.) Following the insertion into the right atrium, thedistal portion of catheter 38 is advanced toward an interatrial septum72 of the heart (FIG. 1A).

Following the passing of the apparatus into the right atrium, guidewire60 is partially withdrawn until the distal end of the guidewire does notprotrude from the distal end of needle 32, at aguidewire-partial-withdrawal step 156, as shown in FIG. 1B. Such partialwithdrawal of the guidewire may expedite the post-puncture deployment ofthe guidewire into the left side of the heart. Upon being partiallywithdrawn, the guidewire remains inside the lumen of needle 32 andwithin the subject's body during the puncturing of the fossa ovalis. Forexample, the guidewire may be withdrawn a distance into the needle ofbetween 0 cm (i.e., just to the distal tip of the needle) and 50 cm(e.g., to the proximal end of the needle, such as between 0 cm and 25cm. In other applications, the guidewire is completely withdrawn fromthe catheter at guidewire-partial-withdrawal step 156.

Typically, at a flexible-longitudinal-member-deployment step 158, asshown in FIG. 1C, flexible longitudinal member 14 (e.g., afossa-ovalis-finding loop) is then deployed from the wall of thecatheter, such that (i) a deployed portion of the flexible longitudinalmember is loop-shaped, and (ii) the needle is on a first side of thedeployed portion of the flexible longitudinal member. Typically, theflexible longitudinal member is deployed such that a deployment angletheta of the flexible longitudinal member is at least 10 degrees and/orless than 80 degrees, e.g., between 30 and 60 degrees. Deployment angletheta is defined as the angle between (a) a vector 64 that is tangent tothe flexible longitudinal member at an exit point 68 of the flexiblelongitudinal member, and is directed away from the catheter, and (b) adistally-directed vector 66 that is parallel to the longitudinal axis 70of the catheter at exit point 68. (Exit point 68 is identical to one ofopenings 26 a and 26 b.) As described hereinabove, the flexiblelongitudinal member is deployed by passing the flexible longitudinalmember through openings 26 a and 26 b. The catheter is steered untilfossa ovalis 18 (e.g., an inner perimeter of the fossa ovalis) iscontacted with the deployed portion of the flexible longitudinal member,as shown in FIG. 1C. Alternatively, another site of the right atrialwall is contacted with the deployed portion of the flexible longitudinalmember, as described hereinbelow with reference to FIG. 13.

Subsequently, at a fossa-ovalis-puncturing step 160, the fossa ovalis ofthe subject is punctured with the needle, as shown in FIG. 1D, typicallywhile needle 32 is within dilator element 49, as shown in the figure.Typically, in order to puncture the fossa ovalis with the needle,dilator tip 16 is brought into contact with the fossa ovalis. The needleis then advanced through a distal opening of the dilator tip and throughthe fossa ovalis, thus puncturing a hole in the fossa ovalis. Dilatortip 16 then dilates the hole created by the needle, also as shown inFIG. 1D. Alternatively, interatrial septum 72 is punctured outside fossaovalis 18, such as described hereinbelow with reference to FIG. 12.Further alternatively or additionally, the hole is created using energyapplied with the needle, rather than force-based mechanical puncturingby the needle, as described hereinbelow with reference to FIG. 15.

As shown in FIG. 1D, prior to puncturing the fossa ovalis, the distalend of needle 32 is typically passed through the deployed portion of theflexible longitudinal member to a second side of the deployed portion ofthe flexible longitudinal member that is opposite the first side. (Thedistal end of the needle is typically passed through the loop whiledisposed inside of the dilator element.)

Typically, catheter 38 is flexibly and/or rotatably steerable viacontrol wires 80 running through control-wire channels 20. Thesteerability of catheter 38 facilitates better localization of thedesired puncturing point. Furthermore, a distal flexible portion of theneedle (described hereinabove with reference to FIGS. 4-7), while it isinside the catheter lumen, may be flexed by steering the catheter.Following the flexing of the distal portion of the needle, the needle isused to puncture the fossa ovalis. The flexing of the needle facilitatesthe puncturing of the fossa ovalis at the desired location, and/or atthe desired angle of the needle relative to the fossa ovalis.Furthermore, owing to the flexibility of the needle, there is generallyno need to bend (i.e., pre-shape) the needle prior to insertion of theneedle into the subject; rather, the needle may be advanced toward theheart of the subject while in a generally straight position, withoutnecessarily using a stylet to maintain the straight position.

At a guidewire-deployment step 162, as shown in FIGS. 1D and 1E,guidewire 60 is deployed (i.e., advanced) into the left side of theheart (including into the left atrium), to facilitate the delivery oftreatment. Guidewire 60 may be deployed into the left atrium along withneedle 32 and/or dilator element 49, as shown in FIG. 1D, or guidewire60 may be deployed into the left atrium after advancing needle 32 and/ordilator element 49 into the left atrium. Guidewire 60 is optionallyadvanced distally out of the distal end of the needle 32 and/or dilatorelement 49 while needle 32 and/or dilator element 49 are in the leftatrium (as shown in FIG. 1E). Alternatively or additionally, needle 32and/or dilator element 49 is withdrawn proximally while holding theguidewire axially stationary, such that the guidewire extends distallyout of needle 32 and/or dilator element 49. In either case, such distaldeployment of the guidewire may help avoid slippage of the guidewireinto the right atrium as needle 32 and/or dilator element 49 iswithdrawn into the left atrium, as described hereinbelow with referenceto FIG. 1F. (As noted above, in some applications, the deployment of theguidewire is relatively quick, as the guidewire remains inside the lumenof the needle during the puncturing of the fossa ovalis.) For someapplications, the deployed portion of flexible longitudinal member 14 iswithdrawn toward the catheter while the distal end of the needle is onthe second side of the deployed portion of the flexible longitudinalmember (also as shown in FIG. 1E).

At an apparatus removal step 164, at least a portion (e.g., all) ofapparatus 34 is removed from the right atrium and, typically, from thebody of the subject. Guidewire 60 remains in the left atrium at thisstep of the procedure. For some applications, such as shown in FIG. 1F,needle 32 (and dilator element 49, if provided) are proximally withdrawnfrom the right atrium, while catheter 38 is left in the right atrium foruse at left-side therapeutic delivery step 166, described hereinbelow.For other applications (not shown), catheter 38 is also withdrawn fromthe right atrium, and a separate catheter is introduced for performingleft-side therapeutic delivery step 166.

At a left-side therapeutic delivery step 166, a left-side therapeuticdelivery system 74 is introduced (i.e., advanced) over guidewire 60,through the hole in the fossa ovalis, and into the left atrium, as shownin FIG. 1G. For example, left-side therapeutic delivery system 74 maycomprise a delivery tool (e.g., comprising one or more tubes), and avalve repair or replacement device or a left atrial appendage implant.Left-side therapeutic delivery system 74 is introduced through catheter38, if catheter 38 has been left in the right atrium, or through anothercatheter, if catheter 38 has been withdrawn from the right atrium.

Reference is now made to FIGS. 11A-B, which are schematic illustrationsof an alternative method for delivering left-side therapeutic deliverysystem 74 to the left side of the heart, in accordance with anapplication of the present invention. In this alternative method, afterdilator element 49 has been advanced into the left atrium, as describedhereinabove with reference to FIG. 1E, catheter 38 is further advanceddistally through the dilated hole in the fossa ovalis and into the leftatrium, as shown in FIG. 11A. At apparatus removal step 164, as shown inFIG. 11B, needle 32 and dilator element 49 are removed from the rightatrium, while catheter 38 and guidewire 60 are left in the left atriumfor use at left-side therapeutic delivery step 166. Alternatively,guidewire 60 is also withdrawn at apparatus removal step 164, and isthus not used at left-side therapeutic delivery step 166.

Reference is now made to FIG. 12, which is a schematic illustration ofan alternative method of using apparatus 34, in accordance with anapplication of the present invention. Other than as described below,this method is similar to the method shown in FIGS. 1B-C, and may beperformed in combination with any of the apparatus and methods describedherein. This method may be performed with or without the techniquesdescribed herein of partially withdrawing guidewire 60.

In this method, the loop-shaped deployed portion of flexiblelongitudinal member 14 has been deployed against fossa ovalis 18 (e.g.,against an inner perimeter of the fossa ovalis), as describedhereinabove with reference to FIGS. 1B-C. Dilator tip 16 is then broughtin contact with a site 130 on a surface of interatrial septum 72 outsidefossa ovalis 18. Following the contacting, needle 32 is deployed,typically while within dilator element 49, by being advanced through adistal opening of the dilator tip, and through interatrial septum 72 atsite 130, thus puncturing a hole in the interatrial septum.Alternatively or additionally, the hole is created using energy appliedwith the needle, rather than force-based mechanical puncturing by theneedle, as described hereinbelow with reference to FIG. 15. Dilator tip16 then dilates an opening created by the needle. Alternatively, such asif dilator element 49 is not provided, a distal end of needle is broughtdirectly in contact with site 130. Alternatively, site 130 is located ona wall of the right atrium other than on interatrial septum 72.

For some applications, site 130 is disposed superior to fossa ovalis 18,such as shown in FIG. 12. Alternatively, site 130 is disposed in anotherdirection from fossa ovalis 18, such as inferior and/or lateral to fossaovalis 18.

For some applications, such as if site 130 is disposed superior to fossaovalis 18, such as shown in FIG. 12, the distal end of needle 32 is notpassed through the deployed portion of flexible longitudinal member 14to a second side of the deployed portion of flexible longitudinal member14 (unlike in the configuration described hereinabove with reference toFIG. 1C). For other applications, such as if site 130 is disposedinferior to fossa ovalis 18 (not shown) or the direction from catheter38 of deployment of flexible longitudinal member 14 is different fromthat shown, the distal end of needle 32 is passed through the deployedportion of flexible longitudinal member 14 to a second side of thedeployed portion of flexible longitudinal member 14 (similar to theconfiguration described hereinabove with reference to FIG. 1C).

Reference is still made to FIG. 12. In accordance with some applicationsof the present invention, a method is provided for puncturinginteratrial septum 72, the method comprising inserting catheter 38 intothe right atrium, and advancing a distal portion of the catheter towardfossa ovalis 18. Flexible longitudinal member 14 is deployed fromcatheter 38, such that a deployed portion of flexible longitudinalmember 14 is loop-shaped. Fossa ovalis 18 (e.g., an inner perimeter ofthe fossa ovalis) is contacted with the deployed portion of flexiblelongitudinal member 14. Needle 32 is deployed from catheter 38 (eitherbefore, after, or simultaneously with deployment of flexiblelongitudinal member 14 from the catheter). A distal end of the needle isbrought in contact with site 130 on a surface of interatrial septum 72outside fossa ovalis 18, and interatrial septum 72 is punctured at site130 with needle 32. The deployed portion of flexible longitudinal member14 is withdrawn toward catheter 38.

For some applications, the method further comprises, before contactingfossa ovalis 18 with the deployed portion of flexible longitudinalmember 14, moving the deployed portion of the flexible longitudinalmember along the surface of interatrial septum 72, until the flexiblelongitudinal member contacts the fossa ovalis. For some applications,moving the deployed portion of the flexible longitudinal member alongthe surface of the interatrial septum comprises moving the deployedportion of the flexible longitudinal member toward the fossa ovalis frombelow the fossa ovalis.

For some applications, deploying the flexible longitudinal membercomprises deploying the flexible longitudinal member such that adeployment angle of the flexible longitudinal member is between 10 and80 degrees, the deployment angle being an angle between (a) a vectorthat is (i) tangent to the flexible longitudinal member at an exit pointof the flexible longitudinal member from the catheter, and (ii) directedaway from the catheter, and (b) a distally-directed vector that isparallel to a longitudinal axis of the catheter at the exit point, suchas described hereinabove with reference to FIG. 1C. For someapplications, deploying the flexible longitudinal member comprisesdeploying the flexible longitudinal member such that the deploymentangle is between 30 and 60 degrees.

For some applications, deploying the flexible longitudinal member fromthe catheter comprises passing the flexible longitudinal member throughtwo lateral openings at a distal portion of the catheter.

For some applications, the flexible longitudinal member is radiopaque,and wherein the method further comprises using fluoroscopic imaging toview the flexible longitudinal member during and after deploymentthereof.

For some applications, the method further comprises, before puncturingthe fossa ovalis, flexing a distal portion of the needle by steering thecatheter.

Reference is now made to FIG. 13, which is a schematic illustration ofan alternative method of using apparatus 34, in accordance with anapplication of the present invention. Other than as described below,this method is similar to the method shown in FIGS. 1B-C, and may beperformed in combination with any of the apparatus and methods describedherein. This method may be performed with or without the techniquesdescribed herein of partially withdrawing guidewire 60.

In this method, the loop-shaped deployed portion of flexiblelongitudinal member 14 is deployed against a surface of the right atriumother than fossa ovalis 18, such as against a stabilization site 140located (a) on a roof 142 of the right atrium, (b) at the junctionbetween roof 142 and interatrial septum 72, or (c) on interatrial septumsuperior to fossa ovalis 18, in order to stabilize catheter 38 (theopening of the superior vena cava is avoided). Dilator tip 16 is thenbrought in contact with a hole site 144 on a surface of interatrialseptum 72 outside fossa ovalis 18. Following the contacting, needle 32is deployed, typically while within dilator element 49, by beingadvanced through a distal opening of the dilator tip, and throughinteratrial septum 72 at hole site 144, thus puncturing a hole in theinteratrial septum. Alternatively or additionally, the hole is createdusing energy applied with the needle, rather than force-based mechanicalpuncturing by the needle, as described hereinbelow with reference toFIG. 15. Dilator tip 16 then dilates an opening created by the needle.Alternatively, such as if dilator element 49 is not provided, a distalend of needle is brought directly in contact with hole site 144.Alternatively, hole site 144 is located on a wall of the right atriumother than on interatrial septum 72.

Typically, hole site 144 is disposed superior to fossa ovalis 18, suchas shown in FIG. 13. Alternatively, hole site 144 is disposed in anotherdirection from fossa ovalis 18, such as inferior and/or lateral to fossaovalis 18.

Depending on the direction of deployment from catheter 38 of flexiblelongitudinal member 14, the distal end of needle 32 may be passedthrough the deployed portion of flexible longitudinal member 14 to asecond side of the deployed portion of flexible longitudinal member 14(as described hereinabove with reference to FIG. 1C), or may not bepassed through the deployed portion.

For some other applications, such as if apparatus 34 is introduced intothe right atrium from the superior vena cava, stabilization site 140 islocated (a) on an annulus of the tricuspid valve, (b) at the junctionbetween the annulus and interatrial septum 72, or (c) on interatrialseptum 72 inferior to fossa ovalis 18, in order to the stabilizecatheter 38.

Reference is still made to FIG. 13. In accordance with some applicationsof the present invention, a method is provided for puncturinginteratrial septum 72, the method comprising inserting catheter 38 intothe right atrium, and advancing a distal portion of the catheter towardroof 142 of the right atrium. Flexible longitudinal member 14 isdeployed from catheter 38, such that a deployed portion of flexiblelongitudinal member 14 is loop-shaped. Stabilization site 140 iscontacted with the deployed portion of flexible longitudinal member 14,stabilization site 140 being located (a) on roof 142 of the rightatrium, (b) between roof 142 and interatrial septum 72, or (c) oninteratrial septum 72 superior to fossa ovalis 18. Needle 32 is deployedfrom catheter 38 (either before, after, or simultaneously withdeployment of flexible longitudinal member 14 from the catheter). Adistal end of needle 32 is brought in contact with hole site 144 on asurface of interatrial septum 72, and interatrial septum 72 is puncturedat hole site 144 with needle 32. The deployed portion of flexiblelongitudinal member 14 is withdrawn toward catheter 38.

For some applications, deploying flexible longitudinal member 14 fromcatheter 38 comprises passing flexible longitudinal member 14 throughtwo lateral openings at a distal portion of the catheter.

For some applications, the flexible longitudinal member is radiopaque,and wherein the method further comprises using fluoroscopic imaging toview the flexible longitudinal member during and after deploymentthereof.

For some applications, the method further comprises, before puncturingthe interatrial septum, flexing a distal portion of the needle bysteering the catheter.

Reference is made to FIG. 14, which is a schematic illustration of theuse of apparatus 34 in combination with a left-side therapeutic deliverysystem, in accordance with an application of the present invention. Thistechnique may be practiced in combination with any of the techniquesdescribed herein. In this application, a delivery catheter 120 of aleft-side therapeutic delivery system is first inserted into the rightatrium, using techniques known in the art. Apparatus 34, includingcatheter 38 thereof, is advanced through delivery catheter 120 into theright atrium, and is then used to puncture fossa ovalis 18 or anothersite on interatrial septum 72, using techniques described herein.Thereafter, apparatus 34 is withdrawn from the body through deliverycatheter 120, leaving delivery catheter 120 in the heart. Deliverycatheter 120 is used to introduce a left-side therapeutic device, suchas a valve repair or replacement device or a left atrial appendageimplant.

Typically, an outer diameter of delivery catheter 120 equals at least150% of an outer diameter of catheter 38, such as at least 200%. Forexample, the outer diameter of delivery catheter 120 may be between 20and 30 Fr, and the outer diameter of catheter 38 may be between 12 and14 Fr.

For some applications, before withdrawal of apparatus 34 from the body,delivery catheter 120 is advanced over dilator element 49 while thedilator element is disposed within the hole in fossa ovalis 18 or theother site on interatrial septum 72, until a distal end opening ofdelivery catheter 120 is disposed in the left atrium. After withdrawalof apparatus 34 from the body, delivery catheter 120 is used tointroduce the left-side therapeutic device into the left atrium.

Reference is made to FIG. 15, which is a schematic illustration of aconfiguration of apparatus 34, in accordance with an application of thepresent invention. This technique may be practiced in combination withany of the techniques described herein. In this application, needle 32is electrically conductive, and is coupled by one or more conductors 178to a controller 180, which comprises or is in electrical communicationwith an energy source. The controller is configured to drive needle 32to apply an ablating current, e.g., an RF current, to puncture the fossaovalis or interatrial septum 72. Alternatively, instead of using anablating current, other energy may be applied, such as heat, ultrasound,or light (e.g., laser) energy. The energy-based puncturing may beperformed instead of or in combination with the force-based mechanicalpuncturing by the needle. For some applications, the distal tip of theneedle is blunt.

Reference is now made to FIG. 16, which is a schematic illustration of amethod for puncturing the fossa ovalis, in accordance with someapplications of the present invention. Before contacting the fossaovalis with the deployed portion of flexible longitudinal member 14, thedeployed portion of the flexible longitudinal member is moved along asurface of interatrial septum 72, until the flexible longitudinal membercontacts the fossa ovalis. In some applications, as shown in FIG. 16,the deployed portion of the flexible longitudinal member is moved towardthe fossa ovalis from below the fossa ovalis. In some applications, theflexible longitudinal member is radiopaque and/or is coupled to aplurality of radiopaque markers. In such applications, fluoroscopicimaging is used to view the flexible longitudinal member during andafter deployment thereof. For example, fluoroscopic imaging may be usedto view the flexible longitudinal member as it is moved toward the fossaovalis, in order to help identify when the flexible longitudinal memberhas reached the fossa ovalis.

Reference is now made to FIGS. 17-18, which are schematic illustrationsof catheter 38, in accordance with some applications of the presentinvention. FIG. 17 shows a control element 30 (e.g., a control handle)shaped to surround a proximal portion of catheter 38. Control element 30facilitates the steering of the catheter, as well as control of needle32 and/or of flexible longitudinal member 14. As described hereinabovewith reference to FIGS. 2A-B, wall 39 of catheter 38 typically comprisesbraided portion 41 and unbraided portion 43. Typically, control element30 surrounds the catheter such that (a) all of the catheter wall that isdistal to a distal end of the control element comprises braided portion41, and (b) at least 10% of the catheter wall that is proximal to thedistal end of the control element comprises unbraided portion 43.Typically, a length L1 of the braided portion is between 600 and 1000mm, and/or a length L2 of the unbraided portion is between 250 and 400mm.

Typically, a braided wall is preferred to an unbraided wall, because thebraiding reduces the buckling of the catheter when a pushing force isapplied. However, some manufacturing processes limit the number oflateral openings that can be made through a braided wall; thus, in orderto allow for the proximal lateral openings 84 shown in FIG. 18, it maybe necessary, when using such manufacturing processes, to make theproximal portion of the catheter wall unbraided. Some applications ofthe present invention compensate for the use of an unbraided wall, byincluding a reinforcing tube 82 that at least partially surrounds theunbraided portion of the catheter wall. Reinforcing tube 82 providesstability to the catheter, in lieu of the braiding.

As shown in FIG. 18, a wall of the reinforcing tube is typically shapedto define one or more lateral openings 84 therethrough. (Openings 84 arealigned with lateral openings in the catheter wall.) Control wires 80,and/or flexible longitudinal member 14, pass through openings 84 intochannels 20, 27 a, and 27 b, shown in FIGS. 2A-B. Control element 30 iscoupled to control wires 80, and/or to flexible longitudinal member 14.

The scope of the present invention includes embodiments described in thefollowing applications, which are assigned to the assignee of thepresent application and are incorporated herein by reference. In anembodiment, techniques and apparatus described in one or more of thefollowing applications are combined with techniques and apparatusdescribed herein:

-   -   U.S. Provisional Application 61/811,947, filed Apr. 15, 2013;    -   U.S. application Ser. No. 14/245,135, filed Apr. 4, 2014, which        published as US Patent Application Publication 2014/0309675;    -   International Application PCT/IL2014/050338, filed Apr. 7, 2014,        which published as PCT Publication WO 2014/170890;    -   U.S. application Ser. No. 14/287,470, filed May 27, 2014, which        published as US Patent Application Publication 2014/0309678;    -   U.S. application Ser. No. 14/287,523, filed May 27, 2014, which        published as US Patent Application Publication 2014/0309679;    -   U.S. application Ser. No. 14/513,435, filed Oct. 14, 2014, which        published as US Patent Application Publication 2016/0100859;    -   U.S. Provisional Application 62/095,150, filed Dec. 22, 2014;        and    -   U.S. application Ser. No. 14/636,759, filed Mar. 3, 2015, which        issued as U.S. Pat. No. 9,668,674; and    -   PCT application PCT/IL2015/051026, filed on Oct. 14, 2015,        entitled, “Fossa ovalis penetration,” which published as PCT        Publication WO 2016/059638.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

The invention claimed is:
 1. A method comprising: transvascularly inserting a guidewire into a right atrium of a subject; providing an apparatus that includes (a) a catheter and (b) a hollow needle disposed within a lumen of the catheter, the hollow needle including a proximal portion and a distal portion that is more flexible than the proximal portion; passing the apparatus into the right atrium by passing the needle over the guidewire; following the passing of the apparatus into the right atrium, partially withdrawing the guidewire into the needle, while keeping a distal end of the guidewire within the needle and in a body of the subject; and after the partially withdrawing of the guidewire into the needle, forming a hole through an interatrial septum of the subject with the needle.
 2. The method according to claim 1, further comprising, after the forming of the hole through the interatrial septum, advancing the guidewire into a left atrium of the subject.
 3. The method according to claim 2, further comprising, after the advancing of the guidewire into the left atrium, proximally withdrawing the needle from the right atrium.
 4. The method according to claim 3, further comprising, after the proximally withdrawing of the needle from the right atrium, introducing, over the guidewire, a left-side therapeutic delivery system into the left atrium.
 5. The method according to claim 4, wherein the proximally withdrawing of the needle from the right atrium comprises leaving the catheter in the right atrium, and wherein the introducing of the left-side therapeutic delivery system comprises introducing the left-side therapeutic delivery system through the catheter.
 6. The method according to claim 4, wherein the method further comprises, before the introducing of the left-side therapeutic delivery system into the left atrium, advancing the catheter distally through the hole into the left atrium, and wherein the introducing of the left-side therapeutic delivery system into the left atrium comprises advancing the left-side therapeutic delivery system through the catheter into the left atrium.
 7. The method according to claim 1, wherein the forming of the hole through the interatrial septum comprises forming the hole through a fossa ovalis of the subject.
 8. The method according to claim 1, wherein the forming of the hole through the interatrial septum comprises puncturing the interatrial septum with a sharp distal tip of the needle.
 9. The method according to claim 1, wherein the forming of the hole through the interatrial septum comprises applying energy to the interatrial septum with the needle.
 10. The method according to claim 1, further comprising, before the forming of the hole through the interatrial septum: deploying at least one fossa-ovalis-finding loop from a wall of the catheter; and moving the fossa-ovalis-finding loop along the interatrial septum, until the fossa-ovalis-finding loop contacts a fossa ovalis of the subject.
 11. The method according to claim 1, wherein the partially withdrawing of the guidewire comprises partially withdrawing the guidewire a distance of less than 50 cm.
 12. The method according to claim 1, wherein the apparatus further includes a fluid-impermeable cover surrounding the distal portion of the needle.
 13. The method according to claim 12, further comprising measuring, using a pressure sensor disposed in fluid communication with a proximal end of the needle, a pressure at a distal tip of the needle.
 14. The method according to claim 1, wherein the apparatus further includes a dilator element, which is shaped to define a dilator lumen and to be slidably disposed within the lumen of the catheter, wherein the needle is slidably disposed within the dilator lumen, and wherein the method further comprises dilating the hole using the dilator element.
 15. The method according to claim 14, further comprising, after the dilating of the hole, advancing the catheter distally through the dilated hole into a left atrium of the subject.
 16. The method according to claim 1, wherein the hollow needle further includes a distal-most end portion that is (a) disposed distal to the flexible distal portion and (b) less flexible than the flexible distal portion.
 17. The method according to claim 1, wherein the catheter is a puncture-tool catheter, and wherein the passing of the apparatus into the right atrium comprises: inserting a delivery catheter of a left-side therapeutic delivery system into the right atrium; and advancing the puncture-tool catheter through the delivery catheter into the right atrium.
 18. The method according to claim 17, further comprising, after the forming of the hole: withdrawing the puncture-tool catheter from the body through the delivery catheter; and using the delivery catheter to introduce a left-side therapeutic device into a heart.
 19. The method according to claim 18, wherein the apparatus further includes a dilator element, which is shaped to define a dilator lumen and to be slidably disposed within the lumen of the puncture-tool catheter, wherein the needle is slidably disposed within the dilator lumen, wherein the method further comprises dilating the hole using the dilator element, and wherein the using of the delivery catheter to introduce the left-side therapeutic device into the heart comprises: advancing the delivery catheter over the dilator element while the dilator element is disposed within the hole through the interatrial septum, until a distal end opening of the delivery catheter is disposed in a left atrium; and after the withdrawing of the puncture-tool catheter from the body through the delivery catheter, using the delivery catheter to introduce the left-side therapeutic device into the left atrium.
 20. The method according to claim 1, wherein the distal portion of the hollow needle is helical. 